n. / Tracing basics
Trace ID
Definition
A trace ID is the unique identifier shared by every span in one trace, so a backend can gather all the steps of a single run back together. It is usually a random 128-bit value written as 32 hexadecimal characters.
In more detail
Each span carries the trace ID of the run it belongs to, plus its own span ID. When spans arrive out of order, or from different services, the trace ID is what lets them be grouped into one timeline. Putting the trace ID in your application logs and error reports is the quickest way to jump from a user complaint to the exact run.
Example
A support agent replies with a wrong refund amount. The reply handler logs trace ID 4bf92f3577b34da6a3ce929d0e0e4736. Searching that ID in the trace viewer opens the whole run, including the tool call that returned the wrong order total.
Related terms
